Method for gasification of bituminous coal



Aug. 20, 1929. J RUsBY 1,725,739

I METHOD FOR GASIFICATION OF BITUMINOUS COAL Filed June 7, 1923 2 Sheets-Sheet 1 Aug. .20, 1929. J RUsBY 1,725,739

METHOD on GASIFICATION 0F BITUMINOUS COAL 'Filed June 7, 1925 2 Sheets-Sheet 2 wmm SWW.

A fro/m5 y Patented Aug. 20, 1929.

UNITED STATES 1,125,139: PATENT OFFICE.

JOHN M. RUSBY, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO THE U. G. I. CON- TRACTIEN'G COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OI DELAWARE.

METHOD FOR GASIIIOA'IION OF BITUMINOUS COAL.

Application filed June 7, 1923. Serial No. 643,859.

The principal objects of the present invention are, first, to effect the complete or partial gasification of bituminous coal or like material in a single bed and therefore in one vessel; second to use that fuel 1n such a way that its valuable volatile portlon will be conserved in substantially its entlrety; third, to effect the carbonization substantially solely by contact with blue water gas;

fourth, to assure a sufliciently hlgh temperature of the blue gas for effecting the carbonization; and sixth, to prepare unusually refractory or wet fuel for carbonizatlon by drying and preheating. Other ob ects of the invention will appear from the following description.

The invention may be said to consist 1n the method of gasifying bituminous coal and the like which comprises establishing a descending fuel bed at the top of whlch such coal is fed and carbonized to coke, alternately heating the entire cross-section of the coke by blasting it from the bottom to the top and from the top to the bottom thereby providing two separate hot zones in the fuel bed and beneath the coal, intermittently generating blue water gas in the lower zone by blasting the fuel bed upward with steam, superheating the blue gas by passing it through the upper zone, and carbonizing the coal to cokesubstantially solely by the superheated blue water gas.

The invention also comprises the method above described with the additional step of preheating the soft coal prior to carbonization by circulating gas through the hot zones and through the freshly charged coal.

The invention also comprises the improvements to be presently described and finally 4.0 claimed.

In the following description reference will be made to the accompanying drawings forming part hereof and in which Figure l is an elevational view, partly in 4.5 section, of apparatus embodying features of the invention and adapted for the practice of the method of the invention and Fig. 2 is a similar view illustrating a modification and showing in a highly diagrammatic fashion an illustration helpful in the description of the method.

Referring to the drawin s a, b, c and d, indicate a descending fuel ed at the top of the bottom, in a manner that will be presgo ently described, thereby providin separate hot zones, 6 and d, in the fuel bed. The zones are referred to by reference letters b and d for the sake of description and not to indicate precise location or extent. Alternately with the air blasting step water gas is generated in the lower coke zone d by blasting the entire fuel bed (coke and coal) upward with steam, and the blue water gas generated at d is raised to an appropriate 7 temperature for carbonizing the coal ata by passing the blue water gas generated at zone d through the heated zone I), and then through the coal so that the coal at a is carbonized by the superheated blue water gas. The resultant gas (water gas and coal gas) is led off from aby 17, 18 and 19 for use for any purpose.

The water gas generator consists of a single vessel 1 enclosing the carbonization so chamber 2 and an underlying gasification chamber 3 in communication with the chamber 2. 4 is'a grate arranged in the chamber 3. 5 is an air blast main which by way of the valves 6 and 6 discharges blast either through the ports 7 to the top of the chamber 8 or by the connection 8 to the bottom .of the chamber 3. When air blast is directed downward from the top to; the bottom of the chamber 3 the connection 9 is 0 closed by the valve 10 and the outlet from the bottom of the chamber 3 is by way of 8 either to the stack 11 or to the pipe 12 accordin to the position of the valves 13 and 14. U sually the air blast gas is led off 5 from 12, for use either in a waste heat boiler or in an apparatus for carbureting water gas. Neither of these is shown because they are too well understood to require description or illustration. When air blast is directed upward from the bottom to the top of the chamber 3 the valve 6 is closed, the valve 6 is open to let air pass from 5 to 8, and valve 10 is in position to close the connection 8 and to open the connection 9, 106 and the blast passes downward through the connection 8 u through the chamber 3 and by the rts to the connection 9 from which t e blast gas is passed either to the stack 11 or to the connection 12 according to the position of the valves 13 and 14. 15 is a steam connection for blasting with steam upward through the chamber 3 and through the chamber 2 and passing the resultin gas to the off-take 16 by way of the pipe 1 branch 18 and seal box 19, the valve at 20 being open. The valves 6 and 6 are closed and the pi e 9 is closed by the valve 10. The pipes 1 21, impeller 22, pipe 23 and check valve 24, provide a means for continuously circulatin' gas from the top of the chamber 2 to theTiottom of the chamber 3 and then to the top of the chamber 2. 25 is a stirrer. 26 is a branch connection provided with a valve 27 and its purpose is to provide for the recovery of valuable hy-- drocarbons that may be driven off from the bituminous coal as will be described.

The carbonizing of the coal is done in 2, whence it descends as coke to 3. 3 is air blasted upwardl establishing a hot zone at about (5. The biast products pass off at the ports 7 as has been described. Thereafter for a brief period the air blast from 5 and 6 is applied through the ports 7 downward through the fuel in 3, thus establishing an intensely hot zone at about I). The blast products pass off as has been described that is, from the bottom of the chamber 3 by way of 8 either to the stack 11 or to the pipe 12 according to the position of the valves 13 and 14:. Steam is then admitted at 28 (shown in Fig. 1 but not in Fig. 2, because in Fig. 2 the wall that carries it is not shown) resulting in the rapid production of blue water gas, though of comparatively low temperature, at the zone 03, which gas thereafter rises and is highly superheated in the zone I). This superheated water gas is forced upward through the bituminous coal at 0:, and the mixture of blue water gas and evolved coal gas is discharged through the seal box 19 and ofl'take 16 to a holder or otherwise appropriately disposed of.

If the freshly charged bituminous coal at the top of 2 is wet or 1f the coal is unusually refractory to carbonization, then, and preferably immediately, after charging the fresh coal the gaseous contents of the generator is caused to circulate by the impeller 22 and its connections up through the hot fuel bed in chamber 3, there heated and then discharged upward through the coal in the chamber 2 whereby the latter is dried and heated; during this circulation of course 'all valves for admission of air or steam or for exit of gases to the atmosphere or elsewhere are closed so as to seal the entire generator to anything but the just described circulation of gas, except that whatever surplus gas may be produced in this circulation process will be continuously discharged through 18 and 19 to the gas holder or elsewhere as desired. This circulation can be continued to whatever extent is desirable. If this recirculation be done with proper attention to the temperature of the hot fuel bed in 3, whatever volatile matter from the coal is thus recirculated need not be seriously injured thereby; the temperature of the fuel bed can be controlled, as necessary, by alternating the above described air blasting and blue water gas making operations with this recirculation. The gas thus drawn from the top of the generator and recirculated is sufliciently low in temperature to be easily handled by an impeller 22 of any Well known type.

The device 25 is provided for agitating, periodically or continuously as may be desired, the bituminous coal. This maintains the freshly charged coal open and freely permeable to the hot blue water gas and also breaks up and renders thus porous the coke formed in the process of carbonization.

29 are openings or stoke holes through which bars may be inserted for assistin the descent of the fuel, for removing clin ers, and for stoking the fire. 30 is a means for supplying fresh coal to the generator.

Although the carbonization of the bituminous coal in 2 will be accomplished almost entirely during the actual passage of water gas therethrough, there may nevertheless be a small amount of distillation of volatiles from the coke, by accumulating heat during the time that 3 is being air blasted and. no gas is passing through the coal in 2. Should it be desired to conserve even this small amount of volatile matter the small valved connection 26 is availed of and the opening of this passage to any desired and controlla ble extent will permit the discharge through the top of 19 and thence through 16 tothe holder, of this evolved volatile matter.

The foregoing describes apparatus for the production of mixed blue (uncarbureted) water gas and coal gas. Should it be desired to carburet this mixture of blue gas and coal gas the connection 31 shown in Fig. 2 diagrammatically represents the change necessary in the apparatus shown in Fig. 1. Referring to Fig. 2fthe pipe 12 is connected to the inlet of the carbureting vessel of a carbureted water gas set and is used for the passage of the air blast gas thereto, and the connection 31 serves for the passage of the mixed blue water gas and coal gas to that vessel. In the modification shown in-Fig. 2. the seal box 19 and its connections as shown in Fig. 1, will not be as there arranged but will be transferred to the outlet of the carbureting vessel which is its usual and well understood location in carbureted Water gas apparatus. Of course the pipe 12 of Fig. 2 may be used for delivering a mix- IOU ture of air blast gas and blue water gas and coal gas and it also can be used to delivergas to the inlet of a waste heat boiler.

It may also be pointed out that the air blasting alternately from the top to the bottom, and from the bottom to the top of the chamber 3, results in comparative uniformity of heating and other effects through the entire cross-section of the coke in the regions where the air blast is applied.

The foregoing described method of pro viding the upper hot zone 6 by down blasting with air is the preferable method, this insuring the greatest uniformity of temperature throughout this zone I). This hot zone can, however, be produced by supplying air blast by the inlets 32, of valved blast branch 33, the blast products being discharged upward through the ports 7 and the connection 9. And such blasting can either be done in alternation with the upward blasting through the grate 4, or can be done in conjunction with this upward blasting; in the latter case, the combustible producer gas issuing upward from the zone 0? will be in part burned and its heat utilized in heating the zone I).

The foregoing description refers to the production of a mixed blue water gas and coal gas which is substantially free from incombustible diluents, especially nitrogen. It is, however, sometimes desired to produce a blue water gas which is mixed with more or less ordinary producer gas which contains incombustible diluents, chiefly nitrogen. In case this mixture is to be produced the desired quantity of blast, or producer, gas from the upward blasting of 3, will be diverted from passage through the ports 7, 9 and 13, to the atmosphere and will instead be passed upward through 2, and thence through 17, 19 and 16 to the holder, or else through 31 and 12 to the carbureted water gas alluded to in connection with Fig. 2. It is evident that in such case the upper hot zone of m process is of great value in superheating 1s roduoer gas before its discharge througli 2 thus assisting in the carbonization of the bituminous coal. It is evident that this supplying of producer gas through 2 and thence to the gas holder, can be done either in conjunction with the roduction of blue water gas in 3 or can a ternate with it, and also that the percentage of producer gas, thus supplied to the holder, or to a carbureted water gas set or other desired point of storage or use, can be made whatever is desired.

It will be obvious that the invention is not limited to details of procedure and con,- struction, or to mere matters of form, or otherwise than as the prior art and the appended claims may require:

I claim:

1. In the method for the complete gasification of bituminous coal in a single vessel; the improvement which consists in maintaining a descending fuel bed at the top of which is uncarbonized coal and at the bottom of which is coke immediately supporting the coal, establishing a bottom hot zone across the entire horizontal area of the coke by air-blasting the coke from the bottom of the coke upward, establishing a second and upper hot zone in the coke immediately supporting the uncarbonized coal by applying to the coke a second independent air-blast at that point, excluding the blast gas from the uncarbonized coal, then generating blue water gas by upwardly steam blasting the coke at the lower hot zone, passing the blue water gas thus formed upward through the upper hot zone whereby the blue water gas is highly heated, and then passing the highly heated blue water gas upward through the superposed coal to efifectv its carbonization to coke.

2. In the method for the complete gasification of bituminous coal in a single vessel; the improvement which consists in maintaining a descending fuel bed at the top of which is uncarbonized coal and at the bottom of which is coke immediately supporting the coal, establishing a bottom hot zone across the entire horizontal area of the coke by air blasting the coke from the bottom of the coke upward, establishing a second and upper hot zone in the coke immediately supporting the uncarbonized coal by applying to the coke a second independent downwardly directed air blast at that point, excluding the blast gas from the uncarbonized coal by leading it off at the bottom of the coke, then generating blue water gas by upwardly steam blasting1 the coke at the lower hot zone, paming t e blue water gas thus formed upward through the upper hot zone whereby the blue water gas is highly heated, and then passin the hi hly heated blue water gas upwar throug the superposed coal to effect its carbonization to coke.

JOHN M. RUSBY. 

